Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1566999 > unrolled thread

[tpmdd-devel] [PATCH v6 2/2] tpm: enhance TPM 2.0 PCR extend to,support multiple banks

Back to article view | Back to linux.kernel

Contents

  [tpmdd-devel] [PATCH v6 2/2] tpm: enhance TPM 2.0 PCR extend  to,support multiple banks Ken Goldman <kgold@linux.vnet.ibm.com> - 2017-01-25 23:20 +0100
    Re: [tpmdd-devel] [PATCH v6 2/2] tpm: enhance TPM 2.0 PCR extend to,  support multiple banks Nayna <nayna@linux.vnet.ibm.com> - 2017-01-30 11:10 +0100

#1566999 — [tpmdd-devel] [PATCH v6 2/2] tpm: enhance TPM 2.0 PCR extend to,support multiple banks

> The current TPM 2.0 device driver extends only the SHA1 PCR bank
> but the TCG Specification[1] recommends extending all active PCR
> banks, to prevent malicious users from setting unused PCR banks with
> fake measurements and quoting them.
>
> The existing in-kernel interface(tpm_pcr_extend()) expects only a
> SHA1 digest.  To extend all active PCR banks with differing
> digest sizes, the SHA1 digest is padded with trailing 0's as needed.
>
> This patch reuses the defined digest sizes from the crypto subsystem,
> adding a dependency on CRYPTO_HASH_INFO module.
>
> [1] TPM 2.0 Specification referred here is "TCG PC Client Specific
> Platform Firmware Profile for TPM 2.0"

Tested-by: Kenneth Goldman <kgold@linux.vnet.ibm.com>

I obtained an IMA event log from a Power platform, along with the PCR 10 
value from both the SHA-1 and SHA-256 banks of its Nuvoton TPM 2.0.  I 
independently validated that the event log matches the TPM PCR values.

[toc] | [next] | [standalone]

#1569539 — Re: [tpmdd-devel] [PATCH v6 2/2] tpm: enhance TPM 2.0 PCR extend to, support multiple banks

On 01/26/2017 03:41 AM, Ken Goldman wrote:
>> The current TPM 2.0 device driver extends only the SHA1 PCR bank
>> but the TCG Specification[1] recommends extending all active PCR
>> banks, to prevent malicious users from setting unused PCR banks with
>> fake measurements and quoting them.
>>
>> The existing in-kernel interface(tpm_pcr_extend()) expects only a
>> SHA1 digest.  To extend all active PCR banks with differing
>> digest sizes, the SHA1 digest is padded with trailing 0's as needed.
>>
>> This patch reuses the defined digest sizes from the crypto subsystem,
>> adding a dependency on CRYPTO_HASH_INFO module.
>>
>> [1] TPM 2.0 Specification referred here is "TCG PC Client Specific
>> Platform Firmware Profile for TPM 2.0"
>
> Tested-by: Kenneth Goldman <kgold@linux.vnet.ibm.com>
>
> I obtained an IMA event log from a Power platform, along with the PCR 10
> value from both the SHA-1 and SHA-256 banks of its Nuvoton TPM 2.0.  I
> independently validated that the event log matches the TPM PCR values.

Thank You Ken !!

Thanks & Regards,
    - Nayna

>
>
> ------------------------------------------------------------------------------
> Check out the vibrant tech community on one of the world's most
> engaging tech sites, SlashDot.org! http://sdm.link/slashdot
> _______________________________________________
> tpmdd-devel mailing list
> tpmdd-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/tpmdd-devel
>

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web